Electron discharge device



April 29, 1947. J. P. I Alco ET AL ELECTRON DISCHARGE DEVICE Filed April 5, 1944 2 Sheets-Sheet 2 AlTTOR/VEV Patented Apr. 29, 1947 UNITED STATES PATENT OFFICEr ELECTRDN DISCHARGE DEVICE Joseph P. Laico, Springfield, N. J., and Victor L.

Ronci, New York, N. Y., assgnors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application April 5, 1944, Serial No. 529,598

6 Claims.

Y manufacture of ultra-high frequency magnetrons.

In one illustrative embodiment o-f this invention, a magnetron of the multicavity type comprises a generally cylindrical anode member, a cathode assembly in cooperative relation with the anode member, leading-in conductors for the cathode assembly, and an output element including a coupling or pick-up loop in cooperative relation with the anode.

In accordance with one feature of this invention, the magnetron is fabricated of three unitary assemblies, namely, a main or anode assembly, an input assembly and an output assembly, constructed and arranged so that the parts of each assembly are accurately associated ina desired relation and when the three assemblies are associated with one another, the cooperating elements, particularly the output or coupling loop and the anode member, are in prescribed relation to one another.

In one specific construction, the main or anode assembly comprises a block provided with a pair of external seating surfaces and a central bore in which a multicavity anode member is inserted, the block having therein a pair of apertures extending from points on the central bore adjacent the ends of the anode member to one of the seating surfaces and having a third aperture extending from a point on the bore adjacent one end of the anode member to the other seating surface. The input assembly comprises a coupler adapted to be seated upon and affixed to the one seating surface above-mentioned, a stem carried by the coupler member and cathode leading-in conductors embedded in the stem and positioned thereby so that when the input assembly is joined to the main assembly the leading-in conductors project through the pair of apertures noted above and into proximity tothe ends of the anode member. 'I'he output assembly includes a second coupler member adapted to be seated upon and affixed to the other seating surface and carrying a stem mounting a linear conductor coaxially with the second coupler, the conductor having a coupling loop at one end thereof. The second coupler memberincludes a sleeve adjacent and coaxially encompassing the one end of the conductor and adapted to fit within the third aperture in the block, whereby when the output assembly is joined to the main assembly the coupling loop is automatically positioned in a desired relation with' respect to the anode'i'nember.

vIn accordance withanother feature of this invention, the sleeve upon the coupler member ex-` tends into the central bore in the block and the anode member is provided with a portion adapted to laterally abut the extending portion of this sleeve thereby to establish a prescribed spacing between the output or coupling loop and the end -of the anode member in juxtaposition thereto.'

In accordance with a further feature of this invention, a tubular conductor intersected by a wave guide element is mounted on the' second coupler member and positioned thereby in coaxial relation With the conductor carrying the output loop and with the wave guide element accurately related to the end of this conductor re mote from the output loop, whereby an accurately coaxial transmission line coupling theoperating region within the device to the wave guide member is provided.

The invention, and the above-noted and other features thereof, willl be understood more clearly' and fully from the following detailed description with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of Van electron discharge device illustrative of one embodiment of this invention;

Fig. 2 is an elevational View of the device shown in Fig. 1 with the heatradiating iins and one end or cover plate of the body assembly removed, and a portion of the input end assembly broken away, the output end assembly being shown mainly in section; l

Fig. 3 is a side elevational'view of the device, mainly in section along plane 3-3 of Fig. 2;

Fig. 4 is a detail View, mainly in section, of the tuning element associated with the anode in the device illustrated in Figs. 1 to 3;

Fig. 5 is another detail view, in section, showing the tuner element for the output wave guide included in the device;

Fig. 6 is a sectional View, to an enlarged scale, of the cathode assembly included in the device; and

Fig. `7 is a fragmentary sectional view showing details of the association of the anode and the quencies corresponding to wavelengths of theA 1 3 order of three centimeters. It comprises basically a main or anode assembly, designated as a Whole as Ill, an input assembly, designated as a whole as II, and an output assembly, designated as a whole as I2.

The main or anode assembly, as shown in Figs.

2 and 3, comprises a substantially square metallic,

for example; copper, block I3, having flanges I4 on one side thereof and having a central cylindrical bore extending therethrough. The block I3 is.

provided on one side with parallel boresor apertures I5 and on another side with an accurately located bore or aperture I5. Fitted within .the central bore in the block i3 and secured tothe block, as by brazing, is a generally annular anode member I1, for example of copper, having therein a plurality of parallel equally spaced, longitudinally extending resonant cavities I 8 and have ing also a plurality of circularly arranged, equally spaced anode segments or elements iS. As shown clearly `Vint Fi'g. 3, thezanode*member.` I1 is-.of a lengthfsubstantially equal to thespacingtbetweenf ample of coppenhaving a centralcircular'dished portion in .which an. insertZZf` of magnetic matee rial.' is'1tt`ed',.the magnetic inserts 22'serving to reduc'ethe.` reluctance ofthe flux pathv for the magneticviieldA parallel to theaxis of the. anode member? I1 ,f utilized. in4 the operation of' the de'- VCe.'

The'input assembly comprisesa metallic couplerior platform member, for example of copper.;

having a cylindrical portion 23 seate'duponthe side `.of Ythe blocklprovided with the flange'M" and herrn'etically sealed thereto asby brazin'g; materialndi'Catedat Eil-,landihaving alsoa aring. portion '25 to which a vitreous stemllhaving a'press 21 is hermetically joined. Sealed in the presse-21T area pair'lofrigid leadingeinconductors 23 which extend into the bores or. apertures I5 and' have joined thereto metallic supports 2S fora cathode` assembly Sillpositioned-fwithin the anode' member I1an'dl accurately coaxial therewith.

The cathode assembly; as shownvclearly 1in Fig. 6,1cornp'ri`sesa cylindrical, metallic cathode member 3l for example of nickel, having enlargedend portions 32 provided with circular flanges 33,-`one ofthe end portions having an integral, centrally offset rib 34 thereon; Fitted about thecathode member 3l is a mesh cylinder 35. In'the fabrication of the assembly, after the mesh cylinderis fitted. in place, amaterial havin'ggood .electron emissive characteristics is' applied. thereto, as by spraying, to form a substantial. electron emissive coating,.not. shown, upon and iirmly. adherent to themesh-V cylinder and to the outerAV surface.. portion of the cathode member between the enlarged end'portionsl 32.- One enlarged` end portion 32 is providednm'tha recessfcr receiving a cylindricall insert 36 of insulating material, carrying ametallic eyelet. 31, the insert SG-being locked inplace byl-fforcingl Darts 38v` ofthis end. portion thereagainst".y Disposed coaxially within the cathode member.` `3l is ahelical heater. lament, 39- coated with an insulating material, the filament having 4 its ends aixed, as by welding, to the n 34 and eyelet 31.

The output assembly, as shown clearly in Fig. 2, comprises a coupler or platform 40, for example of copper, seated upon one side of the block I3 and hermetically joined thereto as by brazing materialindicated at 4 I. The platform has an'integral cylindrical sleeve 42 tted in the aperture I6 and has also integral therewith a flaring portion 43 to which a bulbous vitreous closure or stem 44 is sealed hermetically. The closure 44 is provided with a transverse wall 45 in which one end of a linear output conductor 46 is embedded, the other end of the conductor 46 being joined to one end of a pick-up loop 41. The conductor 46 may terminate in the wall 45 or extend therethrough. The other end of the loop 41 is aixed, as by brazing, to the cylindrical sleeve 42.

As shown in Fig. '7, an end portion of the anode member l1 is removed and the cylindrical sleeve 42- extends into this portion and is engaged laterally by the anode member. The support 46, when embedded.in'thetransverse wall 45, is held inaccurate coaxial relation with thesleeve42 and the loop 41 is thus fixed with respect to the sleeve. The loop 4i is so formed that when the.

platforml is. amxed to the block I3, the loopis parallel tothe juxtaposed face ofthe anode member and substantially coaxial with one of the cavities I8. Inasmuch as. the anode member I1 abutsthesleeve 42 it Will be appreciated that, when the device is fabricated, the output loop 41 is` automatically positioned in accurate, iixed space relation,y to.l the juxtaposed facer of the anode member, whereby close and eflicient coupling between the loopv andy the high frequency eldwithin the anode cavities Iis obtained.

The closure or stem 44 and coupler member 4I),l

eare encompassed by a cylindrical metallic member .48 yixed at one end to thecoupler member. 40.

and positionedthereby coaxial withrthe conductor 45, and intersected. by arectangular wave guide element. 49, the. latter havingv a. coupling.y flange- 50 thereonatone endandbeing locatedsothat its. longitudinal. axis passesthrough the end. of the conductor 45 embedded in the wall 45. When. thedevice is operating,.energy from the high. frequency neldwithin the device is picked up by the loop.' 41 and the conductors 4B and 48-are energized accordingly so that highv frequency-wavesr are .propagated along the wave guide element 49;y

In. the assembly of. the'device, the anodemember.. l1'. is: iixed `in the block I3. TheA metallic member. 23,- 25, stem 21, leading-in conductors: 28-and supports 29 are fabricatedinto aunitary assembly. Another unitary assembly is con structed, of the coupler Amember 41.43,.. closure .l or stem 45, conductor flandoutput loop41. These two-assembliesare then associated withthe block i3,.with the sleeve 42. inl the aperture or bore. I5 and` the conductors 28. extendingA through the apertures orf'bores I5 and with Washersof brazingVH material24 and. 4IA positioned as. shown in the drawings. The twoA assemblies and` theblock are clamped together in the proper relation, as ,by a suitablexture, andthe member. 23and coupler member liV are brazed: to theblock. The cathode is then. held in accuratel coaxial rela,- tionwith theanodesegments I9, by asuitable tool-,and the supportsgarewelded tothe eyelet 31 and n 34. the magnetic inserts v2v2 therein, are. brazedto .the block I3., Alternatively, the cathode may be af.-Y xed to thesupports-ZS before-theinput. and out putassembliesarel brazed to. the. block. I3. In..

Finally, the end plates. 2l with either case, it will be appreciated that the construction :facilitatesA and expedites the manufacture of the device in that the input and output assemblies are fabricable as unitary structures with the parts in prescribed relation and in that vthe output assembly, and more particularly the output loop 41, is automatically positioned by its manner of association withvthe block I3, in the required relation with the anode member I1.

It will be noted that the space relation determining contact areas between the anode block I3 and the coupler members 23 and 40 are directly metal to metal so that the desired relation of the parts is fixed accurately. Specifically, as seen clearly in Fig. 3, the contact area, indicated at 9D, between the coupler 23and the block I3 is directly copper to copper. Similarly, as indicated at SI Vin Fig. 2, the contact between the coupler 40 and the block I3 is directly copper to copper.

i In some devices, it is desirable that'the cavities I8 be tunable so as to obtain exactly a prescribed operating frequency. One construction for thus tuning the device is illustrated in Fig. 4. As shown in thisfigure, the anode member I1 is provided intermediate its ends with a recess 5I having a tapered end portion 52 in one of the cavities I8, into which a metallic plug 53 projects. The plug 53 is carried by an annularly corrugated diaphragm 54 fixed to the block I3 by an insert 55 having an internally threaded sleeve 56 aiiixed thereto. .Extending through the sleeve 56 is a screw 51 havingan end portion 58 provided with a central aperture for receiving a stem 59 in the plug 53. In the fabrication of the tuner assembly, the sleeve 56 is affixed to the insert 55, vas by peening over portions of the inner end thereof, and the insert 55 and diaphragm -54 are brazed to the block I3. Simultaneously with this brazing, the screw 5'! is brazed to the stem 59 extending from the plug 53. The sleeve is then rotatable to move the screw inwardly or outwardly to tune the cavity I8 into which the plug projects to the desired frequency. The screw may then be fixed in this position by a lock nut 1I) thereon. Limitation of the maximum displacement of the screw 51 to prevent destruction of the parts of the tuner is effected in one direction by the juxtaposed faces of the end portion 58 and the sleeve 56, and in the other direction by the juxtaposed faces 93 of the plug 53 and the tapered portion 94 of the recess 5 I.

In order to prevent seizing of cooperating parts of the tuner structure due to high temperatures to which they may be subjected during fabrication of the device, the several bearing or contactf' ing surfaces advantageously are of stainless steel to leaded bronze. For example, the sleeve 56 may be stainless steel and the insert 55 of leaded bronze. A particular advantage of this construction is that, because of the diiferent characters of the materials, after heat treatment of the device, a substantially minimum clearance between the sleeve 56 and insert 55 is provided which allows rotation of the sleeve to actuate the screw 51 but assures substantially no play between the sleeve and the insert.

Advantageously, means are provided for adjusting the effective length of the wave guide member 49 to establish a close match between the impedance thereof and that of the coaxial line 46, 48 associated therewith. In one form, illustrated in Fig. 5, such means comprises a diaphragm 60 at one end of the member 49, specilically the lower end thereof in Fig. 1, having its peripheral portion ailixed to the member 49 and mounting an internally threaded detail or nut 6 I. A disc 62 also is fixed to the member 49 and is provided with a threaded aperture 63 coaxial with the nut or detail 6I. To adjust the constants of the wave guide, a suitable tool is threaded into the nut 6I and disc 62 and rotated to move the diaphragm 6B either inwardly or outwardly as may be required. The diaphragm 60 is of a soft metal that distorts and acquires a permanent set readily. When it has been displaced to the desired position, the tool is removed by unscrewing it from the nut 6I and disc 62.

The device may be supported by a mounting plate or disc 63 which encompasses the stem 26 and extends from a cylinder 64 secured to the metallic member 23.

In order to prevent overheating of the anode assembly during operation of the device, cooling fins may be coupled thermally to the assembly. In one form, illustrated in Fig. 1, the iins 65 are plate members of bent form having edge portions thereof fitted in slots in the block I3 and affixed to the mounting plate 63 by flanges 66 and a bracket 61. The ns 65 are provided with oppositely curved portions 68 to allow ready passage therebetween of a tool for adjusting the tuner screw 5T.

The stem 26 may be enclosed by a protective -cap 69, for example of a vitreous material, mounted upon the supporting plate 63 and carrying terminals, not shown, to which the leadingin conductors 28 are connected.

Although a specic embodiment of this invention has been shown and described, it will be understood that it is but illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention as defined in the appended claims.

What is claimed is:

l. An electron discharge device comprising a block having a pair of external seating surfaces and enclosing an anode member, said block having a pair of apertures extending from one of said seating surfaces to adjacent the ends of said anode member and a third aperture extending from the other of said surfaces to adjacent one end of said anode member, a first assembly comprising la coupler member seated upon said one surface and mounting a pair of leading-in ccnductors extending through said pair of apertures, a cathode adjacent said anode member and supported by said conductors, and a second assembly comprising a coupler member seated upon said other surface and mounting an output conductor extending through said third aperture into proximity to said anode member.

2. An electron discharge device in accordance with claim 1 wherein said second coupler member comprises a sleeve portion tted in said third aperture and extending beyond the inner end thereof and said anode member i-s provided with an end portion abutting said sleeve portion.

3. An electron discharge device comprising a block having a bore extending therethrough and having also an aperture therein communicating with said bore, a coupler member having a sleeve V portion tted in and extending through said l aperture, an output conductor mounted Iby said coupler member, extending through said sleeve portion and having a coupling loop thereon adjacent the inner end of said sleeve portion, an anode member iitted in said bore and abutting said sleeve portion, and a cathode adjacent said anode member.

4. An electron discharge device comprising a v .rectangular metallic block having a longitudinal .bore extending therethrough, said block having also apa-ir of apertures extending from said bore to Yoneside surface of the block and a third aperture extending from said bore to a second side surface of the block, a cylindrical anode member fitted in said bore and extending between the inner ends of said pair of apertures, said third aperture extending from adjacent one end of said anode member, a first unitary assembly comprising 9, coupler member seated on said one surface, a stem carried by said coupler member, and a pair of leading-in conductors sealed in said stem and extending therefrom through said pair of apertures Vand into said bore, a second unitary assembly comprising a coupler member seated upon said'second'suriace, a stem carried by said second coupler member and an output conductor sealed in :said second stemand extending therefrom and coaxially through said third aperture, and a coupling loop adjacent said one end of said Vanode member and connected to said conductor, a cathode 'within said anode member and supported by said leading-in conductors, and closure members at opposite ends of said bore and aixed to said block.

5. An electron discharge device comprising a metallic block having g'longitudinal bore extending 'therethrough and having also an aperture extending from saidY bore to one side surface of thebloe'k, an anode member iitted in said bore and having one end adjacent the inner end of said aperture, a cathode adjacent said anode member, a metallic coupler member seated on said side surface having a sleeve tted in said aperture land an outer cylindrical surface coaxial with said sleeve, a stem secured to said coupler member, a linear conductor-extending coaxially .into said sleeve and having its outer end embedded in said stem, a coupling loop adjacent said kone end of saidanode member and connected to said sleeve and to the other end of said conductor, a tubular membervencompassing said conductor and fitted on said outer cylindrical Surface, and a wave guide member extending from said tubular member and opposite said outer `end of said conductor.

6. An electron discharge device comprising an anode member having a resonant cavity extending longitudinally therethrough and having a laterally extending recess therein communicating with said cavity, a plug member in said recess, a diaphragm secured'to said anode member and mounting said plug member, a screw aixed to said diaphragm, a hollow V'member xed to Ysaid anode member 'and -encompassing said screw, and a sleeve threaded-upon said lscrew and rotatably mount-edby said hollow'member.

JOSEPH P. LAICO. VICTOR L. RONCI.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Y2,348,986 Linder- May 16, 1944 2,167,201 Dallenbach July 25, 1939 FOREIGN PATENTS Numberv Country Date 509,102 British July 11, 1939 

